The present invention relates to an optical information recording device that records information on a recording medium using a holographic memory.
Today, an optical disc with a recording density on the order of 128 GB is produced on a commercial basis according to the Blu-ray Disc (trademark) standard in which a blue-violet semiconductor laser is used. In future, a still larger capacity is desired by taking advantage of the ability to conserve data for long periods of time that is one of the merits of an optical disc. The problem with the technology described above is that increasing the recording density on a disc surface is approaching the limit. Realizing a super-dense recording, such as 1 TB or higher per one disc, on an optical disc requires a new high-density recording technology that is different from the high-density recording technology based on a shorter wavelength and an object lens with higher NA. The study has been conducted on the next-generation storage technology and, in particular, attention has been paid to the hologram recording technology that records digital information using hologram.
A technology for positioning a recording medium at a reproduction time is disclosed, for example, in JP-A-2007-304263. This document describes that “the signal for driving a holographic memory in the focus direction, radial direction, and tangential direction is generated based on the FE signal, RE signal and TE signal, and this signal is applied to the actuator that three-dimensionally drives the holographic memory.
By doing so, a positioning error in the hologram, which is reproduced, in the focus direction, radial direction, and tangential direction is corrected.